Russia's richest man shouldn't get too comfortable with the view from the top. Leonid Mikhelson, the gas and petrochemical magnate who topped Russia's rankings in this year's Forbes Billionaires List, was the seventh person to occupy the top spot in the past decade.

Economic sanctions, political intrigue, a fluctuating currency and one of the world's most volatile stock markets have combined to make Russian fortunes remarkably fickle. In recent years, falling metals prices have also depressed the value of key holdings for Russia's once-richest tycoons. It's not unusual for Russia's "oligarch" billionaires to double or halve their fortunes within a few years.

In the United States, by contrast,
Microsoft cofounder Bill Gates has been the richest man for 15 out of the past 16 years (his friend, investor Warren Buffet, overtook him in 2008). China has been nearly as volatile as Russia, with six people cycling through the number one rank in the past decade.

In a bad year for Russia's ultra-rich, Mikhelson topped the list with a net worth of just $14.4 billion; he was actually $1.2 billion richer in 2014, when he was only fifth in line. He has a stake in natural gas producer
Novatek and is the largest shareholder in Sibur, a gas processing and petrochemical company that sold 10% of its shares to Chinese state-owned
Sinopec for $1.3 billion in December. Mikhelson debuted on the list with a net worth of $2.5 billion ten years ago, after building on his father's leadership of the largest pipeline construction trust in the Soviet Union.

Mikhelson took over the number one spot from Vladimir Potanin, chairman and key shareholder of metals giant
Norilsk Nickel. Before that, Alisher Usmanov managed to hold on to the position for three years with a peak net worth of $18.6 billion in 2014. He also made his fortune in metals, retaining stakes in iron ore and steel giant Metalloinvest and Norilsk Nickel, then invested in everything from Facebook to telecom. As of mid-February 2016, Usmanov's fortune dropped to $12.5 billion, mostly due to falling iron and steel prices and a weakening ruble.

Vladimir Lisin, the richest man in 2010 and 2011, peaked at a net worth of $24 billion in 2011 thanks to rising stock prices for his publicly traded firm,
Novolipetsk Steel. By 2016, he had less than half left after steel prices fell; his net worth for this year's list was $9.3 billion.

Even more dramatic was the fall of Oleg Deripaska. In 2008 he was the richest Russian and the ninth-richest person in the world, worth $28 billion. After facing billions of dollars in debt due to the 2008 financial crisis, and the steep decline in the value of his stake in aluminum company
UC Rusal, his fortune cratered to a mere $2.1 billion for the 2016 Forbes list.

I cover the richest people on the planet as part of Forbes’ wealth team. I report on how billionaires make, spend and lose their fortunes and track wealth across the globe for the Forbes World’s Billionaires list and the Forbes 400 Richest Americans list. I’m interested in h...